Cigarette and aerosol generation device for cigarette

ABSTRACT

Provided is a cigarette including: a tobacco rod; a first air flow delivery element adjacent to a first end of the tobacco rod and having a first porosity; and a second air flow delivery element adjacent to a second end of the tobacco rod and having a second porosity greater than or equal to the first porosity, wherein the second porosity is greater than or equal to 30%.

TECHNICAL FIELD

The present disclosure relates to a cigarette and an aerosol generatingapparatus therefor.

BACKGROUND ART

Recently, the demand for alternative methods to overcome theshortcomings of traditional cigarettes has increased. For example, thereis growing demand for a method of generating aerosol by heating anaerosol generating material in cigarettes, rather than by combustingcigarettes. Accordingly, studies on a heating-type cigarette and aheating-type aerosol generating device have been actively conducted.

DESCRIPTION OF EMBODIMENTS Technical Problem

According to an embodiment, a cigarette may include a filter located ata rear end and having a greater porosity than a filter located at afront end.

Solution to Problem

According to an aspect of the present disclosure, a cigarette mayinclude: a tobacco rod; a first air flow delivery element adjacent to afirst end of the tobacco rod and having a first porosity; and a secondair flow delivery element adjacent to a second end of the tobacco rodand having a second porosity greater than or equal to the firstporosity, wherein the second porosity is greater than or equal to 30%.

The first porosity may be greater than or equal to 10% and less than orequal to 30%.

A ratio of the second porosity to the first porosity may be greater thanor equal to 1 and less than 3.

The second air flow delivery element may have a tube shape having aninner diameter formed by a hollow.

A ratio of the inner diameter of the second air flow delivery element toan outer diameter of the second air flow delivery element may be greaterthan or equal to 55%.

The inner diameter may be greater than or equal to 3.0 mm and less thanor equal to 4.5 mm.

The first air flow delivery element and the second air flow deliveryelement may include cellulose acetate.

According to another aspect of the present disclosure, an aerosolgenerating apparatus may include: a case; a heater heating a cigaretteincluding a tobacco rod, a front-end plug adjacent to a front end of thetobacco rod and having a first porosity, and a filter rod adjacent to arear end of the tobacco rod and having a second porosity greater than orequal to the first porosity, wherein the second porosity is greater thanor equal to 30%; a vaporizer generating an aerosol by vaporizing aliquid composition and delivering the aerosol into the cigarette throughthe front-end plug; and a controller controlling operations of theheater and the vaporizer.

Advantageous Effects of Disclosure

According to an embodiment, a cigarette may include a filter located ata rear end and having a porosity greater than a porosity of a filterlocated at a front end to thereby cool mainstream smoke and a surfacetemperature of the cigarette at a safe temperature.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view of a cigarette according to an embodiment.

FIG. 2 is a perspective view of a cigarette according to anotherembodiment.

FIGS. 3 and 4 are diagrams illustrating examples in which a cigarette isinserted into an aerosol generating apparatus.

FIG. 5 is a cross-sectional view taken along line A-A′ of FIG. 1 andillustrating a flow of air passing through the cigarette of FIG. 1.

FIG. 6 is a cross-sectional view of the cigarette of FIG. 1 respectivelytaken along lines B-B′ and C-C′ of FIG. 1.

FIG. 7 is a view illustrating examples of a point where a temperature ofmainstream smoke and a surface temperature of a cigarette are measuredin the cigarette, according to an embodiment.

BEST MODE

According to an aspect of the present disclosure, a cigarette mayinclude: a tobacco rod; a first air flow delivery element adjacent to afirst end of the tobacco rod and having a first porosity; and a secondair flow delivery element adjacent to a second end of the tobacco rodand having a second porosity greater than or equal to the firstporosity, wherein the second porosity is greater than or equal to 30%.

According to another aspect of the present disclosure, an aerosolgenerating apparatus may include: a case; a heater heating a cigaretteincluding a tobacco rod, a front-end plug adjacent to a front end of thetobacco rod and having a first porosity, and a filter rod adjacent to arear end of the tobacco rod and having a second porosity greater than orequal to the first porosity, wherein the second porosity is greater thanor equal to 30%; a vaporizer generating an aerosol by vaporizing aliquid composition and delivering the aerosol into the cigarette throughthe front-end plug; and a controller controlling operations of theheater and the vaporizer.

MODE OF DISCLOSURE

With respect to the terms used to describe the various embodiments,general terms which are currently and widely used are selected inconsideration of functions of structural elements in the variousembodiments of the present disclosure. However, meanings of the termscan be changed according to intention, a judicial precedence, theappearance of new technology, and the like. In addition, in certaincases, a term which is not commonly used can be selected. In such acase, the meaning of the term will be described in detail at thecorresponding portion in the description of the present disclosure.Therefore, the terms used in the various embodiments of the presentdisclosure should be defined based on the meanings of the terms and thedescriptions provided herein.

In addition, unless explicitly described to the contrary, the word“comprise” and variations such as “comprises” or “comprising” will beunderstood to imply the inclusion of stated elements but not theexclusion of any other elements. In addition, the terms “-er”, “-or”,and “module” described in the specification mean units for processing atleast one function and/or operation and can be implemented by hardwarecomponents or software components and combinations thereof.

As used herein, an “aerosol generating article” may refer to a materialcapable of generating an aerosol, such as a tobacco (cigarette) and acigar. The aerosol generating article may include an aerosol generatingmaterial or an aerosol forming substrate. Also, the aerosol generatingarticle may include a solid material based on a tobacco raw materialsuch as a reconstituted tobacco sheet, shredded tobacco, andreconstituted tobacco. An aerosol may include a volatile compound.

Also, the term “upstream” or “front” refers to a direction away from themouth of a user smoking an aerosol generating article, and the term“downstream” or “rear” may refers to a direction closer to the mouth ofthe user smoking the aerosol generating article.

Hereinafter, the present disclosure will now be described more fullywith reference to the accompanying drawings, in which exemplaryembodiments of the present disclosure are shown such that one ofordinary skill in the art may easily work the present disclosure. Thedisclosure may, however, be embodied in many different forms and shouldnot be construed as being limited to the embodiments set forth herein.

Hereinafter, embodiments of the present disclosure will be described indetail with reference to the drawings.

FIG. 1 is a perspective view of a cigarette according to an embodiment.

Referring to FIG. 1, a cigarette 3 includes a tobacco rod 31, a filterrod 32, and a front-end plug 33. The tobacco rod 31 includes a tobaccomaterial and an aerosol generating material. The tobacco material may betobacco.

The filter rod 32 may be adjacent to an end of the tobacco rod 31. Forexample, the filter rod 32 may be adjacent to a rear end of the tobaccorod 31. The filter rod 32 may include a single segment or a plurality ofsegments. For example, the filter rod 32 may include a first segment 321for cooling an aerosol and a second segment 322 for filtering aparticular component included in the aerosol.

The front-end plug 33 may be adjacent to an end of the tobacco rod 31.For example, the front-end plug 33 may be located on a side of thetobacco rod 31, the side not facing the filter rod 32. The front-endplug 33 may be adjacent to a front end of the tobacco rod 31. Thefront-end plug 33 may prevent the tobacco rod 31 from being falling offand prevent a liquefied aerosol from flowing into an aerosol generatingapparatus 1 of FIGS. 1-3 from the tobacco rod 31 during smoking.

The cigarette 3 may be packaged by at least one wrapper 35. The wrapper35 may surround the cigarette 3.

A diameter of the cigarette 3 may be within a range of about 5 mm toabout 9 mm, and a length thereof may be about 48 mm, but embodiments arenot limited thereto. For example, the tobacco rod 31 may include atleast one of glycerin, propylene glycol, ethylene glycol, dipropyleneglycol, diethylene glycol, triethylene glycol, tetraethylene glycol, andoleyl alcohol, but it is not limited thereto. Also, the tobacco rod 31may include other additives, such as flavors, a wetting agent, and/ororganic acid. Also, the tobacco rod 31 may include a flavored liquid,such as menthol or a moisturizer, which is injected to the tobacco rod31.

The tobacco rod 31 may be manufactured in various forms. For example,the tobacco rod 31 may be formed using a sheet or strands. Also, thetobacco rod 31 may be formed as shredded tobacco, which is obtained byfinely cutting a tobacco sheet. Also, the tobacco rod 31 may besurrounded by a heat conductive material The filter rod 32 may include acellulose acetate filter. Shapes of the filter rod 32 are not limited.For example, the filter rod 32 may include a cylinder-type rod or atube-type rod having a hollow inside. Also, the filter rod 32 mayinclude a recess-type rod. When the filter rod 32 includes a pluralityof segments, at least one of the plurality of segments may have adifferent shape.

Hereinafter, each segment of the filter rod 32 will be described indetail.

The first segment 321 of the filter rod 32 may cool an aerosol that isgenerated when the tobacco rod 31 is heated by a heater 13. Therefore, auser may puff the aerosol that is cooled at an appropriate temperature.

The first segment 321 may be a filter that blocks preset components,such as foreign substances, before a gas from the tobacco rod 31 entersthe second segment 322.

Also, the first segment 321 may be an air flow delivery element thatdelivers a gas from a front end thereof to a rear end thereof byproviding a path through which the gas discharged from the tobacco rod31 moves.

The first segment 321 may include an empty space through which a gas maymove.

The empty space may be a hollow or a passage having a polygonal crosssection and extending in a longitudinal direction. Alternatively, theempty space may be a plurality of small holes of the first segment 321formed of a porous material.

The porosity of the first segment 321 may be variously determined by theempty space. The porosity may indicate a proportion of an area occupiedby the empty space in a total cross-sectional area of the first segment321. The porosity may be designed in consideration of a cooling effectof an air flow and the amount of nicotine transfer.

The empty space and the porosity may be designed in various shapes anddimensions, and embodiments thereof will be described in more detaillater with reference to FIG. 6.

A length or diameter of the first segment 321 may be variouslydetermined according to a shape of the cigarette 3. For example, thelength of the first segment 321 may be an appropriate length within arange of about 7 mm to about 20 mm. Preferably, the length of the firstsegment 321 may be about 14 mm, but is not limited thereto.

According to an embodiment, the first segment 321 of the filter rod 32may be a cellulose acetate filter. Also, the first segment 321 may bemanufactured by inserting, into an inside (e.g., a hollow) thereof, astructure such as a film or tube which is formed of the same ordifferent material.

For example, the first segment 321 may be a tube-type structure having ahollow inside. The first segment 321 may prevent an internal material ofthe tobacco rod 31 from being pushed back when the heater 13 is insertedand may also generate a cooling effect of an aerosol. A diameter of thehollow included in the first segment 321 may be an appropriate diameterwithin a range of about 2 mm to about 4.5 mm, but is not limitedthereto.

According to another embodiment, the first segment 321 may bemanufactured by weaving a polymer fiber. In this case, a fiber formed ofpolymer may be coated with a flavored liquid. Alternatively, the firstsegment 321 may be manufactured by weaving together an additional fibercoated with a flavored liquid and a fiber formed of polymer.Alternatively, the first segment 321 may be formed by a crimped polymersheet. As a result, a surface area contacting the aerosol may beincreased. Therefore, an aerosol cooling effect of a cooling structuremay be further improved.

For example, polymer may be formed of a material selected from the groupconsisting of polyethylene (PE), polypropylene (PP), polyvinyl chloride(PVC), polyethylene terephthalate (PET), polylactide (PLA), celluloseacetate (CA), and aluminum foil.

As the first segment 321 may be formed by the woven polymer fiber or thecrimped polymer sheet, the first segment 321 may include a singlechannel or a plurality of channels extending in a longitudinaldirection. Here, a channel refers to a passage through which a gas(e.g., air or an aerosol) passes.

The first segment 321 may include a thread including a volatile flavorcomponent. Here, the volatile flavor component may be menthol but is notlimited thereto. The second segment 322 of the filter rod 32 may be acellulose acetate filter. A length of the second segment 322 may be anappropriate length within a range of about 4 mm to about 20 mm. Forexample, the length of the second segment 322 may be about 14 mm orabout 12 mm, but is not limited thereto.

In a process of manufacturing the second segment 322, a flavor may beprovided by injecting a flavored liquid onto the second segment 322.Alternatively, an additional fiber coated with a flavored liquid may beinserted into the second segment 322. An aerosol generated in thetobacco rod 31 is cooled by passing through the first segment 321, andthe cooled aerosol is delivered to the user through the second segment322. Therefore, when a flavored liquid is added to the second segment322, an effect of enhancing the persistence of a flavor delivered to theuser may be generated.

The front-end plug 33 may be an air flow delivery element that deliversa gas from a front end thereof to a rear end thereof by providing a paththrough which the gas discharged from the tobacco rod 31 moves.

The front-end plug 33 may include an empty space through which a gas maymove.

The empty space may be a hollow or a passage having a polygonal crosssection and extending in a longitudinal direction. Alternatively, theempty space may be a plurality of holes in the front-end plug 33 formedof a porous material.

The porosity of the front-end plug 33 may be variously determined by theempty space. The porosity may indicate a proportion of an area occupiedby the empty space in a total cross-sectional area of the front-end plug33. The porosity may be designed in consideration of a cooling effect ofan air flow and the amount of nicotine transfer.

The empty space and the porosity may be designed in various shapes anddimensions, and embodiments thereof will be described in more detaillater with reference to FIG. 6.

The porosity of the front-end plug 33 may be less than the porosity ofthe first segment 321. As such, an air flow exiting the front-end plug33 may expand while passing through the first segment 321, therebycooling the air flow and increasing the amount of nicotine transfer.This will be described in more detail later with reference to FIG. 5.

The front-end plug 33 may be formed of cellulose acetate. Also, asneeded, the front-end plug 33 may include at least one channel, and across-sectional shape of the channel may be formed in various shapes.

FIG. 2 is a perspective view of a cigarette according to anotherembodiment.

The above description with reference to FIG. 1 may be applied to acigarette 3 that will be described with reference to FIG. 2. FIG. 2illustrates additional features which may be included in the cigarette 3described above with reference to FIG. 1.

A wrapper 35 may include a plurality of wrappers surrounding respectivesegments.

For example, a front-end plug 33 may be packaged by a first wrapper 351,a tobacco rod 31 may be packaged by a second wrapper 352, a firstsegment 321 may be packaged by a third wrapper 353, and a second segment322 may be packaged by a fourth wrapper 354. Also, the entire cigarette3 may be repackaged by a fifth wrapper 355.

The first wrapper 351 may be a combination of general plug wrap paperand metal foil such as aluminum foil. The second wrapper 352 and thethird wrapper 353 may be formed of general plug wrap paper. For example,the second wrapper 352 and the third wrapper 353 may be porous plug wrappaper or non-porous plug wrap paper.

The wrapper 35 may have at least one perforation 36 formed therein. Airoutside the cigarette 3 may be introduced into the cigarette 3 throughthe perforation 36 formed in the wrapper 35.

The perforation 36 may be formed in various locations. For example, theperforation 36 may be formed in the fifth wrapper 355. Air introducedthrough the fifth wrapper 355 may be introduced into the cigarette 3 bypassing through an inner wrapper surrounded by the fifth wrapper 355.

As another example, the perforation 36 may be formed in an areasurrounding a filter rod 32. In detail, the perforation 36 may be formedin an area surrounding the first segment 321. Here, air introducedthrough the perforation 36 may cool heated air and cool a surface of thefilter rod 32 before the heated air passing through the tobacco rod 31reaches the mouth of a user.

The perforation 36 may be formed in various numbers. For example, threeperforations 36 may be formed or nine perforations 36 may be formed.Here, a distance between the perforations 36 may be constant or theperforations 36 may be formed at different distances with a presetpattern.

FIGS. 3 and 4 are diagrams illustrating examples in which a cigarette isinserted into an aerosol generating apparatus.

Referring to FIG. 3, the aerosol generating device 1 may include abattery 11, a controller 12, and a heater 13. Referring to FIG. 4, theaerosol generating device 1 may further include a vaporizer 14. Also,the cigarette 3 may be inserted into an inner space of the aerosolgenerating device 1.

FIGS. 3 through 4 only illustrate components of the aerosol generatingdevice 1, which are particularly related to the present embodiment.Therefore, it will be understood by one of ordinary skill in the artrelated to the present embodiment that other general-purpose componentsmay be further included in the aerosol generating device 1, in additionto the components illustrated in FIGS. 3 through 4.

Also, FIG. 4 illustrate that the aerosol generating device 1 includesthe heater 13. However, as necessary, the heater 13 may be omitted.

FIG. 3 illustrates that the battery 11, the controller 12, and theheater 13 are arranged in series. Also, FIG. 4 illustrates that thebattery 11, the controller 12, the vaporizer 14, and the heater 13 arearranged in series. However, the internal structure of the aerosolgenerating device 1 is not limited to the structures illustrated inFIGS. 3 through 4. In other words, according to the design of theaerosol generating device 1, the battery 11, the controller 12, theheater 13, and the vaporizer 14 may be differently arranged.

When the cigarette 3 is inserted into the aerosol generating device 1,the aerosol generating device 1 may operate the heater 13 and/or thevaporizer 14 to generate an aerosol from the cigarette 3 and/or thevaporizer 14. The aerosol generated by the heater 13 and/or thevaporizer 14 is delivered to a user by passing through the cigarette 3.

As necessary, even when the cigarette 3 is not inserted into the aerosolgenerating device 1, the aerosol generating device 1 may heat the heater13.

The battery 11 may supply power to be used for the aerosol generatingdevice 1 to operate. For example, the battery 11 may supply power toheat the heater 13 or the vaporizer 14, and may supply power foroperating the controller 12. Also, the battery 11 may supply power foroperations of a display, a sensor, a motor, etc. mounted in the aerosolgenerating device 1.

The controller 12 may control overall operations of the aerosolgenerating device 1. In detail, the controller 12 may control not onlyoperations of the battery 11, the heater 13, and the vaporizer 14, butalso operations of other components included in the aerosol generatingdevice 1. Also, the controller 12 may check a state of each of thecomponents of the aerosol generating device 1 to determine whether ornot the aerosol generating device 1 is able to operate.

The controller 12 may include at least one processor. A processor can beimplemented as an array of a plurality of logic gates or can beimplemented as a combination of a general-purpose microprocessor and amemory in which a program executable in the microprocessor is stored. Itwill be understood by one of ordinary skill in the art that theprocessor can be implemented in other forms of hardware.

The heater 13 may be heated by the power supplied from the battery 11.For example, when the cigarette 3 is inserted into the aerosolgenerating device 1, the heater 13 may be located outside the cigarette3. Thus, the heated heater 13 may increase a temperature of an aerosolgenerating material in the cigarette 3.

The heater 13 may include an electro-resistive heater. For example, theheater 13 may include an electrically conductive track, and the heater13 may be heated when currents flow through the electrically conductivetrack. However, the heater 13 is not limited to the example describedabove and may include all heaters which may be heated to a desiredtemperature. Here, the desired temperature may be pre-set in the aerosolgenerating device 1 or may be set as a temperature desired by a user.

As another example, the heater 13 may include an induction heater. Indetail, the heater 13 may include an electrically conductive coil forheating a cigarette in an induction heating method, and the cigarettemay include a susceptor which may be heated by the induction heater.

For example, the heater 13 may include a tube-type heating element, aplate-type heating element, a needle-type heating element, or a rod-typeheating element, and may heat the inside or the outside of the cigarette3, according to the shape of the heating element.

Also, the aerosol generating device 1 may include a plurality of heaters13. Here, the plurality of heaters 13 may be inserted into the cigarette3 or may be arranged outside the cigarette 3. Also, some of theplurality of heaters 13 may be inserted into the cigarette 3 and theothers may be arranged outside the cigarette 3. In addition, the shapeof the heater 13 is not limited to the shapes illustrated in FIGS. 3through 4 and may include various shapes.

Referring to FIG. 4, the aerosol generating apparatus 1 may furtherinclude the vaporizer 14.

The vaporizer 14 may generate an aerosol by heating a liquid compositionand the generated aerosol may pass through the cigarette 3 to bedelivered to a user. In other words, the aerosol generated via thevaporizer 14 may move along an air flow passage of the aerosolgenerating device 1 and the air flow passage may be configured such thatthe aerosol generated via the vaporizer 14 passes through the cigarette3 to be delivered to the user.

For example, the vaporizer 14 may include a liquid storage, a liquiddelivery element, and a heating element, but it is not limited thereto.For example, the liquid storage, the liquid delivery element, and theheating element may be included in the aerosol generating device 1 asindependent modules.

The liquid storage may store a liquid composition. For example, theliquid composition may be a liquid including a tobacco-containingmaterial having a volatile tobacco flavor component, or a liquidincluding a non-tobacco material. The liquid storage may be formed to beattached to and detached from the vaporizer 14, or may be formedintegrally with the vaporizer 14.

For example, the liquid composition may include water, a solvent,ethanol, plant extract, spices, flavorings, or a vitamin mixture. Thespices may include menthol, peppermint, spearmint oil, and variousfruit-flavored ingredients, but are not limited thereto. The flavoringsmay include ingredients capable of providing various flavors or tastesto a user. Vitamin mixtures may be a mixture of at least one of vitaminA, vitamin B, vitamin C, and vitamin E, but are not limited thereto.Also, the liquid composition may include an aerosol forming substance,such as glycerin and propylene glycol.

The liquid delivery element may deliver the liquid composition of theliquid storage to the heating element. For example, the liquid deliveryelement may be a wick such as cotton fiber, ceramic fiber, glass fiber,or porous ceramic, but is not limited thereto.

The heating element is an element for heating the liquid compositiondelivered by the liquid delivery element. For example, the heatingelement may be a metal heating wire, a metal hot plate, a ceramicheater, or the like, but is not limited thereto. In addition, theheating element may include a conductive filament such as nichrome wireand may be positioned as being wound around the liquid delivery element.The heating element may be heated by a current supply and may transferheat to the liquid composition in contact with the heating element,thereby heating the liquid composition. As a result, aerosol may begenerated.

For example, the vaporizer 14 may be referred to as a cartomizer or anatomizer, but it is not limited thereto.

The aerosol generating device 1 may further include general-purposecomponents in addition to the battery 11, the controller 12, the heater13, and the vaporizer 14. For example, the aerosol generating device 1may include a display capable of outputting visual information and/or amotor for outputting haptic information. Also, the aerosol generatingdevice 1 may include at least one sensor Also, the aerosol generatingdevice 1 may be formed as a structure where, even when the cigarette 3is inserted into the aerosol generating device 1, external air may beintroduced or internal air may be discharged.

Although not illustrated in FIGS. 3 through 4, the aerosol generatingdevice 1 and an additional cradle may form together a system. Forexample, the cradle may be used to charge the battery 11 of the aerosolgenerating device 1. Alternatively, the heater 13 may be heated when thecradle and the aerosol generating device 1 are coupled to each other.

The cigarette 3 may be similar as a general combustive cigarette. Forexample, the cigarette 20000 may be divided into the tobacco rod 31including an aerosol generating material and the filter rod 32 includinga filter, etc. The filter rod 32 of the cigarette 3 may also include anaerosol generating material. For example, an aerosol generating materialmade in the form of granules or capsules may be inserted into the filterrod 32.

The entire tobacco rod 31 may be inserted into the aerosol generatingdevice 1, and the filter rod 32 may be exposed to the outside.Alternatively, only a portion of the tobacco rod 31 may be inserted intothe aerosol generating device 1, or the entire tobacco rod 31 and aportion of the filter rod 32 may be inserted into the aerosol generatingdevice 1. The user may puff aerosol while holding the filter rod 32 bythe mouth of the user. In this case, the aerosol is generated by theexternal air passing through the tobacco rod 31, and the generatedaerosol passes through the filter rod 32 and is delivered to the user'smouth.

For example, the external air may flow into at least one air passageformed in the aerosol generating device 1. For example, opening andclosing of the air passage and/or a size of the air passage may beadjusted by the user. Accordingly, the amount and quality of the aerosolmay be adjusted by the user. As another example, the external air mayflow into the cigarette 3 through at least one hole formed in a surfaceof the cigarette 3.

FIG. 5 is a cross-sectional view taken along line A-A′ of FIG. 1,illustrating a flow of air passing through a cigarette of FIG. 1.

Referring to FIG. 5, when the user smokes by using the cigarette 3, airmay flow into the cigarette 3 through the front-end plug 33, carry agenerated aerosol while passing through the tobacco rod 31, and reachthe mouth of the user by passing through the first segment 321 and thesecond segment 322 of the filter rod 32.

The porosity of the first segment 321 may be greater than the porosityof the front-end plug 33. As such, a gas including air and mainstreamvapor which exits the front-end plug 33 and enters the first segment 321may instantaneously expand in volume. Therefore, the gas may be cooledwhile expanding. Also, the gas may diffuse in a radial direction of thecigarette 3 while entering the first segment 321. Here, thedirectionality of an air flow moving downstream is reduced, which makesthe gas stay longer in the first segment 321. As a result, a coolingeffect may be improved.

As a difference in the porosity between the front-end plug 33 and thefirst segment 321 becomes greater, the cooling effect of the gasdescribed above may be improved. In other words, as the porosity of thefirst segment 321 becomes greater, the cooling effect of the gasdescribed above may be improved.

For example, when the first segment 321 is a tube type having a hollow,the porosity increases as an inner diameter increases, thereby improvinga cooling effect of a gas. When the front-end plug 33 is a tube type, tothe extent that the inner diameter of the first segment 321 is greaterthan an inner diameter of the front-end plug 33, the cooling effect ofthe gas may be improved.

Also, the porosity of the front-end plug 33 and the first segment 321may affect the draw resistance with respect to an air flow and theamount of nicotine carried by the air flow. As the porosity of the firstsegment 321 becomes greater, the amount of air introduced may increase,and the draw resistance may decrease. As a result, the transfer amountof nicotine-including aerosol generated in the tobacco rod 31 mayincrease.

Therefore, the porosity, the inner diameter values, and the like of thefront-end plug 33 and the first segment 321 may be determined inconsideration of the draw resistance, the transfer amount of aerosol,and the cooling effect of the gas.

FIG. 6 is a cross-sectional view of a cigarette of FIG. 1 respectivelytaken along lines B-B′ and C-C′ of FIG. 1. The cross sections of FIGS.6A and 6B are merely examples of cross sections of the cigarette 3 butare not limited thereto.

FIG. 6A is a cross-sectional view of the cigarette 3 taken along lineB-B′. Referring to FIG. 6A, a cross section of the cigarette 3 mayinclude an empty space in which a plurality of slit-shaped or rod-shapedspaces are combined. The cross section of FIG. 6A may be a cross sectionof the front-end plug 33.

For example, the empty space may have a Y shape in which threeslit-shaped or rod-shaped empty spaces having different extensiondirections are combined.

The porosity of the cross section of the cigarette 3 may vary accordingto the number, thickness, and length of the slit-shaped or rod-shapedempty spaces. For example, a total cross-sectional area of the cigarette3 may be 38.5 mm², and a cross-sectional area of the empty space may be10.89 mm². Here, the porosity of the cigarette 3 may be 28.3%.

As another example, the total cross-sectional area of the cigarette 3may be 38.5 mm², and the cross-sectional area of the empty space may be8.21 mm². Here, the porosity of the cross section of the cigarette 3 maybe 21.3%. As another example, the total cross-sectional area of thecigarette 3 may be 38.5 mm², and the cross-sectional area of the emptyspace may be 5.75 mm². Here, the porosity of the cross section of thecigarette 3 may be 14.9%. In other words, referring to FIG. 6A, theporosity of the cross section of the cigarette 3 may be greater than orequal to about 10% and less than about 30%.

The cross section of FIG. 6A is merely an example of the cross sectionof the cigarette 3, and embodiments are not limited thereto. Forexample, the cross section of the cigarette 3 may include one, two, fouror more slit-shaped or rod-shaped empty spaces. Here, the porosity mayincrease with an increase in the number of slit-shaped or rod-shapedempty spaces.

FIG. 6B is a cross-sectional view of the cigarette 3 taken along lineC-C′. Referring to FIG. 6B, the cross section of the cigarette 3 mayhave a tube shape having a hollow formed therein. FIG. 6B mayillustrate, for example, a cross section of the first segment 321.

An inner diameter of the hollow may be designed to provide presetporosity. The porosity may increase with an increase in the innerdiameter of the hollow and may decrease with a decrease in the innerdiameter of the hollow.

For example, a total diameter of the cigarette 3 may be within a rangeof about 5 mm to about 9 mm. In detail, the diameter of the cigarette 3may be about 7 mm to about 7.4 mm.

Here, the inner diameter of the hollow may be in a range of 3.0 mm and4.5 mm. Preferably, the inner diameter of the hollow may be greater thanor equal to 3.8 mm. More preferably, the inner diameter of the hollowmay be greater than or equal to 4.0 mm.

As a result, the inner diameter of the hollow may be greater than orequal to 50% of the total diameter of the cigarette 3. In detail, theinner diameter of the hollow may be greater than or equal to 55% of thetotal diameter of the cigarette 3.

A total cross-sectional area of the cigarette 3 may be 38.5 mm², and across-sectional area of an empty space due to the hollow may be 13.85mm². Here, the porosity of the cross section of the cigarette 3 may begreater than or equal to 30%. In detail, the porosity of the crosssection of the cigarette 3 may be 36.0%.

As described above with reference to FIGS. 6A and 6B, the porosity ofthe cross section of the cigarette 3 may be differently designedaccording to a cross-sectional shape of the cigarette 3. For example,the first segment 321 may have a hollow-shaped cross section with aporosity greater than or equal to 30% as illustrated in FIG. 6B, and thefront-end plug 33 may have a cross section including a Y-shaped emptyspace having a porosity greater than or equal to 10% and less than 30%as illustrated in FIG. 6A. In other words, a ratio of the porosity ofthe first segment 321 to the porosity of the front-end plug 33 may begreater than or equal to 1 and less than 3.

FIG. 7 is a view illustrating a location where a temperature ofmainstream gas and a surface temperature of a cigarette are measured inthe cigarette, according to an embodiment. FIG. 7A is a cross-sectionalview of a cigarette 3 cut in a longitudinal direction, and FIG. 7B is aperspective view of the cigarette 3. A perforation 36 may be located inthe wrapper surrounding a first segment 321.

Table 1 below shows data about a mainstream gas temperature of thecigarette 3, a surface temperature of the cigarette 3, and the amount ofnicotine transfer, which are measured by varying a ratio of porosity ofa first segment 321 to porosity of a front-end plug 33. As illustratedin FIG. 7A, the first segment 321 and a second segment 322 are adjacentto each other, and a mainstream gas temperature is measured in area A1through which mainstream gas passes. The mainstream gas temperature maybe measured through a temperature sensor. As illustrated in 7B, asurface temperature is measured in an area A2 of the center of a surfaceof the second segment 322. The surface temperature may be measuredthrough a thermal imaging analysis.

TABLE 1 Experimental Experimental Experimental Classification Example #1Example #2 Example #3 First Segment Porosity (%) 12.8 23.6 36.0Front-end Plug Porosity (%) 28.3 Cigarette Surface 50.0 53.0 53.0Temperature (° C.) Mainstream Smoke 62.0 58.6 56.2 Temperature (° C.)Nicotine Transfer Amount 0.60 0.66 0.71 (mg/cigarette)

An empty space cross-sectional area of the front-end plug 33 is 10.89mm², and the porosity thereof is 28.3%. In each experimental example,the empty space cross-sectional area of the front-end plug 33 is 10.89mm², and thus, the porosity of a cross section of the front-end plug 33is maintained at 28.3%. In the first experimental example, the firstsegment 321 may have a tube shape having a hollow, and an outer diameterof the first segment 321 may be about 7 mm to about 7.4 mm. An innerdiameter of the first segment 321 is 2.5 mm. A ratio of the innerdiameter of the first segment 321 to the outer diameter of the firstsegment 321 is 34%. An empty space cross-sectional area of the firstsegment 321 is 4.91 mm², and thus, the porosity of a cross section ofthe first segment 321 is 12.8%.

In the second experimental example, the inner diameter of the firstsegment 321 is 3.4 mm. A ratio of the inner diameter of the firstsegment 321 to the outer diameter of the first segment 321 is 46%. Theempty space cross-sectional area of the first segment 321 is 9.07 mm²,and thus, the porosity of the cross section of the first segment 321 is23.6%.

In the third experimental example, the inner diameter of the firstsegment 321 is 4.2 mm. A ratio of the inner diameter of the firstsegment 321 to the outer diameter of the first segment 321 is 56%. Theempty space cross-sectional area of the first segment 321 is 13.85 mm²,and thus, the porosity of the cross section of the first segment 321 is36.0%.

Referring to Table 1 above, as described above with reference to FIG. 5,as the porosity of the first segment 321 increases, the surfacetemperature and the mainstream gas temperature of the cigarette 3decrease, and the amount of nicotine transfer increases.

In particular, when the porosity of the front-end plug 33 is less than30% and the porosity of the first segment 321 is greater than or equalto 30%, the mainstream gas temperature may be as low as 56.2° C., andthe amount of nicotine transfer may be as high as 0.71 mg/cigarette.

Those of ordinary skill in the art related to the present embodimentsmay understand that various changes in form and details can be madetherein without departing from the scope of the characteristicsdescribed above. The disclosed methods should be considered in adescriptive sense only and not for purposes of limitation. The scope ofthe present disclosure is defined by the appended claims rather than bythe foregoing description, and all differences within the scope ofequivalents thereof should be construed as being included in the presentdisclosure.

What is claimed is:
 1. A cigarette comprising: a tobacco rod; a firstair flow delivery element adjacent to a first end of the tobacco rod andhaving a first porosity; and a second air flow delivery element adjacentto a second end of the tobacco rod and having a second porosity greaterthan or equal to the first porosity, wherein the second porosity isgreater than or equal to 30%.
 2. The cigarette of claim 1, wherein thefirst porosity is in a range of 10% to 30%.
 3. The cigarette of claim 1,wherein a ratio of the second porosity to the first porosity is greaterthan or equal to 1 and less than
 3. 4. The cigarette of claim 1, whereinthe second air flow delivery element has a tube shape having an innerdiameter formed by a hollow.
 5. The cigarette of claim 4, wherein aratio of the inner diameter of the second air flow delivery element toan outer diameter of the second air flow delivery element is greaterthan or equal to 55%.
 6. The cigarette of claim 4, wherein the innerdiameter is in a range of 3.0 mm to 4.5 mm.
 7. The cigarette of claim 1,wherein the first air flow delivery element and the second air flowdelivery element include cellulose acetate.
 8. An aerosol generatingapparatus comprising: a case; a heater configured to heat a cigarettecomprising: a tobacco rod; a front-end plug adjacent to a front end ofthe tobacco rod and having a first porosity; and a filter rod adjacentto a rear end of the tobacco rod and having a second porosity greaterthan or equal to the first porosity, wherein the second porosity isgreater than or equal to 30%; a vaporizer configured to generate anaerosol by vaporizing a liquid composition and delivering the aerosolinto the cigarette through the front-end plug; and a controllerconfigured to control operations of the heater and the vaporizer.